An evaporation fuel purge system has a pump which pumps evaporation fuel. Such a system is used for a vehicle such as hybrid car or idling stop vehicle, in which processing time of evaporation fuel is comparatively short, or a vehicle having an engine with a turbocharger or a low friction engine car, in which a negative pressure is small at an intake manifold.
JP 4082004 B2 (corresponding to US 2002/0162457 A1) describes such a system, in which evaporation fuel is drawn from a canister with a purge pump, and the evaporation fuel is sent to an intake passage for an engine through a purge control valve. The purge pump is arranged on a piping through which evaporation fuel flows.
Since the evaporation fuel pumped by the purge pump passes through the purge pump, a flameproof structure is needed for the purge pump. Moreover, when the purge pump stops, the purge pump itself may be a resistance for a flow of evaporation fuel.